目前国内采用的围生期时间范围是( )
A.妊娠20周至产后l周
B.妊娠20周至产后2周
C.妊娠28周至产后l周
D.妊娠28周至产后2周
E.妊娠28周至产后3周
参考答案:C
He is an _____ boy from a small village in Guangxi. [ ]
A. eight-year-old
B. eight-years-old
C. eight year old
VBA中定义符号常量的关键字是【 】。